When a photon is created, it instantly achieves the speed of light -- How?

In summary: The process which goes into the photon being created requires the energy that makes it go as fast as it does. This is false, or misleading at best. There is nothing to indicate light having a lower energy limit to make it go at c. All light, no matter how low its energy, moves at c.
  • #1
zuz
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I've been told that when a photon of light is created it instantly achieves the speed of light without having to 'speed up". How is this possible?
 
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  • #2
Pedantically, photons are just light, so whatever speed they go is the speed of light.

To answer the question you are asking, however, the photons are emitted with a certain amount of energy. The process which goes into the photon being created requires the energy that makes it go as fast as it does.
 
  • #3
zuz said:
I've been told that when a photon of light is created it instantly achieves the speed of light without having to 'speed up". How is this possible?

When you drop a pebble onto the surface of water, do you notice the ripple being created speeding up, or do you see it immediately moving at the a particular speed?

There is also no "why" or "how" in this case, the same way we do not have the why's and how's for light having a fix, constant speed in vacuum.

James Chase Geary said:
Pedantically, photons are just light, so whatever speed they go is the speed of light.

To answer the question you are asking, however, the photons are emitted with a certain amount of energy. The process which goes into the photon being created requires the energy that makes it go as fast as it does.

This is false, or misleading at best. It somehow implies that its speed depends on its energy, which is wrong. There is nothing to indicate light having a lower energy limit to make it go at c. All light, no matter how low its energy, moves at c.

Zz.
 
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  • #4
zuz said:
I've been told that when a photon of light is created it instantly achieves the speed of light without having to 'speed up". How is this possible?
Just to add to what others have said, emitted light is not a photon, it's a wave. That is, there are no photons in a beam of light. The wave only creates a photon when it interacts with something. This is important because a lot of people, I think possibly including you, think that the emitted "photon" is like a little tiny billiard ball that goes shooting off at the speed of light.
 
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  • #5
My apologies for my lack of rigor. I wasn't trying to be misleading, just trying to get at the concept in an intuitive way. But yes, of course, the speed doesn't depend on the energy. I just meant to imply that photons were created by a some kind of process already moving at light speed.
 
  • #6
James Chase Geary said:
I just meant to imply that photons were created by a some kind of process already moving at light speed.

which also is not good
what do/did you think was already moving at c ?
 
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1. How is it possible for a photon to instantly achieve the speed of light?

The speed of light is a fundamental constant in the universe, and photons are particles that are always moving at this speed. This means that when a photon is created, it is already traveling at the speed of light. It does not need to accelerate or gain momentum like other particles.

2. What allows a photon to travel at the speed of light?

According to Einstein's theory of relativity, the speed of light is the maximum speed at which anything in the universe can travel. Photons, as particles of light, do not have any mass, which allows them to move at this speed. Additionally, they do not experience any resistance in the form of friction or air resistance, which would slow them down.

3. Is it possible for a photon to slow down or speed up?

No, it is not possible for a photon to change its speed. As mentioned before, the speed of light is a fundamental constant and cannot be changed. Photons always travel at the speed of light, regardless of their energy or wavelength.

4. How is the speed of light related to the energy of a photon?

The speed of light is directly related to the energy of a photon. This is because the energy of a photon is proportional to its frequency, and the frequency of a photon is directly related to its speed. As a photon's energy increases, its frequency and speed also increase.

5. Can anything travel faster than the speed of light?

According to our current understanding of physics, nothing can travel faster than the speed of light. This is because as an object approaches the speed of light, its mass increases, making it more and more difficult to accelerate. At the speed of light, an object's mass would be infinite, and it would require an infinite amount of energy to accelerate it further.

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